Employee deviance is prevalent and could have significant consequences to organizations and/or its members. Drawing upon deterrence theory, this study examined the mediating role of self-regulatory efficacy on the relationship between punishment certainty, punishment severity and organizational deviance. The participants were 197 employed postgraduate students who enrolled in the Master of Business Administration programme at two universities located in the north-west geopolitical zone of Nigeria. The model tested suggests that both punishment certainty and punishment severity predict organizational deviance through the influence of self-regulatory efficacy. Results suggest that self-regulatory efficacy partially mediates the relationship between punishment certainty and organizational deviance. Similarly, results suggest that the relationship between punishment severity and organizational deviance was partially mediated by self-regulatory efficacy.